• 한국운동역학회지
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• 제22권2호
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• pp.209-217
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• 2012

The purpose of this study was to develop a turn-type treatment program which applies the principle of spotting and a roll-type treatment program that induces off-vertical axis. 29 collegiate students volunteered for this study. 12-week treatment programs were applied to both 15 students for turn-type treatment group and 14 students for roll-type treatment group. As an analytic tool, eye camera was employed to verify the treatment programs for a stimulus upon a turn, recovery after a stimulus upon a turn, and nystagmus that affects a vestibular system. Two-way ANOVA with repeated measures was applied to see the significant differences between the treatment groups, and between the test periods. For Post-Hoc Test, paired t-test was used to within the group and independent t-test was used to between the groups. The results indicated that roll-type treatment training has maximized a stimulus on nystagmyus during the stimulus by a roll. Turn-type treatment training has maximized a stimulus on nystagmyus right after a stimulus by a roll and significantly decreased the intensity of nystagmyus during the recovery. Both turn and roll type treatments have reduced the recovery time which from nystagmyus to a normal status. Roll-type treatment has showed a much shorter recovery time for nystagmyus than the roll-type treatment has. Based on the results of treatment programs developed in this study, we expect the treatment programs can be applied to treat dizziness and to improve the function of vestibular system as a rehabilitation tool.

• 대한기계학회논문집A
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• 제20권1호
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• pp.189-205
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• 1996

The twin-roll type strip continuous casting process(or direct rolling process) of steel materials is characterized by two rotating water cooled rolls receiving a steady supply of molten metal which solidifies onto the rolls. A solidification analysis of molten metal considering phase transformation and thermofluid is performed using finite diffefence method with curvilinear coordinate to reduce computing time and molten region analysis with arbitrary shape. An enthalpy-specific heat method is used to determine the temperatures inthe roll and the steel. The temperature distribution of cooling roll is calculated using two dimensional finite element method, because of complex roll shape due to cooling hole in rolls and improvemnt accuracy of calculation result. The energy equaiton of cooling roll is solved simultanuously with the conservation equaiton of molten metal in order to consider heat transfer through the cooling roll. The calculated roll temperature is compared to experimental results and the heat transfer coefficient between cooling roll surface and rolling material(steel) is also determined from comparison of measured roll temperature and calculated temperature.

• 한국해양공학회지
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• 제19권3호
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• pp.25-30
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• 2005

To predict rolling performance for a barge-type FPSO, the evaluation of correct nonlinear roll damping is critical. The square section of FPSO causes a considerable viscous damping effect. Free roll decay tests were carried out to estimate nonlinear roll damping for a barge-type FPSO, under three different conditions. The roll motion RAO was deduced from model tests in the wave condition of the wideband spectrum. In numerical calculation, the quadratic damping was considered as equivalent linear damping, using the results of free roll decay test. Tested roll performance in the JONSWAP wave spectrum was compared with numerical results. These two results shaw good agreement, in spite of the proximity of peak wave period and roll natural period.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.323-324
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• 2006

This paper presents dynamics of register error on a compensator roll type converting machine. Though a register control is an important aspect of a converting machine, it has not been taken into account as a main subject. Lately, demands for high speed converting machines over 500mpm(m/min) are raising but domestic converting industries can not come up with the high speed machines because capacities fur designing of the converting machine is restricted lower than 300mpm. Moreover register control is the key to product flexible displays through roll-to-roll systems. In this paper, a compensator roll type register controller is analyzed using mathematical model of register error. A case study for reducing transient register errors is discussed.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.160-163
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• 2003

For the purpose of rolling hard metals such as silicon steel and non-ferrous metals, the backup roll driven-type mill has been widely used in cold rolling industry. Since the backup roll drive results in horizontal bending of the work rolls and therefore exerted reciprocal action on the roll gap contour, the selection of slim work rolls is very restricted. In this paper, we present an analytic equation based scheme to determine a proper horizontal position of work roll minimizing the horizontal force subject to mechanical constraints.

• 한국해양공학회지
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• 제25권5호
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• pp.40-46
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• 2011

This study carried out a series of experiments involving impact tests (Drop weight type & Charpy type with a standard specimen and newly designed I-type specimen), hardness tests, and fracture surface observations of French-made roll shell steel (F), abnormal roll shell steel (M), reheated roll shell steel (R), and S25C steel under heat treatment conditions ($570^{\circ}C$) to analyze the cause and prevent the roll shell steel's brittle fracture and its damage.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.30-35
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• 2004

Several roll motion reduction devices are reviewed and suggested for the application in FPSO. The firstly suggested solution is the shape of the bilge. The next is a bilge keel. The last suggestion is the ART (anti-rolling tank). Typical U-tube type ART is designed for a FPSO and examined extensively by model experiment. The model section was made of transparent acryl. Free decay test, forced oscillation test and wave test were carried out at a two-dimensional wave flume. U-tube type ART is effective only when the natural periods of ART and ship are same. Therefore, the divided U-tube type ART with split plate is suggested for the reduction of the roll motion of a FPSO over the wide range of the roll period.

• 펄프종이기술
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• 제30권4호
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• pp.69-78
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• 1998

Papers loaded with 10-40% $TiO_2$ by dry weight were calendered under the various combinations of calendering conditions such as calender type, linear pressure, and roll temperature. After being calendered, light scattering coefficient, surface roughness, density, and tensile strength of the papers were measured and the results were summerized as follows: 1. To increase the light scattering coefficient of $TiO_2$-highly-loaded paper further by calendering, the calender roll pressure and temperature should be kept low. Under these conditions, the physical strength of the paper was not significantly affected. 2. At low roll temperature, soft nip calender and machine calender type showed the same relationship between paper density and its roughness. At high roll temperature, soft nip calender type gave much lower roughness than machine calender type at the same density. 3. At high roll temperature of both calenders, the density as well as the tensile strength of the TiO$_2$-loaded paper was increased significantly.

• 동력기계공학회지
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• 제17권3호
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• pp.65-71
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• 2013

The under rail slide is the latest device to make accurate rectilinear reciprocating motion. In these day, 3-point type is used mostly for the products requiring high strength and performance such as refrigerator door guide or furniture drawer guide. However, It is all imported from foreign countries due to lack of the roll forming technique to make 3-point type under rail slide in domestic. Therefore, design and manufacturing technology for the 3-point type under rail slide are need to development through systematic study. In this paper, to make center member of 3-point ball-type under rail slide for the refrigerator doors, the roll forming modeling and simulation are performed using Shape-RF software. Tensile test is performed about SCP-1 1/2H for determine the mechanical properties of materials. Interference between the roll and the final shape are predicted from the results of the simulation ; this result show that the desirable performance and usefulness of the designed roll forming process.

• 한국정밀공학회지
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• 제28권10호
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• pp.1153-1158
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• 2011

Roll-to-roll process is an emerging mass production method for printed and flexible electronics such as touch screen panel, RFID tag, thin film solar cell, and flexible display due to its high throughput. High precision in printing and coating is required to apply functional materials onto substrate. For such reason, every part of the roll-to-roll equipment needs to be precisely fabricated and to retain its precision under regular operation. In this article, the precision of cantilever type idler roller and a novel method to mitigate its deflection under web tension loading are discussed and the method is verified using both the numerical and the experimental works. The proposed method improves the structural rigidity of cantilever type roller whose advantages, such as low capital cost and high web path configurability, are maintained.